The goal of the European Single Market has led to standardization in several areas within the European Union during the last years. However, this is not true for the tax systems that remain part of the autonomous responsibility of each Member State. Given the aforementioned standardization and the high mobility of capital, the tax system of a Member State becomes an increasingly important criterion for investment decisions. The consequence is a permanent competition among Member States to offer an attractive tax framework.The central goal of the research project is a highly detailed qualitative and quantitative analysis of the development of tax burdens in Europe during the last twenty years. For the quantitative analysis, the European Tax Analyzer will be employed. Apart from the comprehensive implementation of different tax systems, the development of tax burdens can be analyzed for different size classes and industries. Different trends (tax rate cut cum tax base broadening, SME-incentives, R&D-incentives, decline of taxes on capital) and their effects on tax burdens will be important parts of the research project. After the analysis, proposals for a further harmonization of tax systems in Europe will be analyzed and enhanced.